Inlined Function Composition

ppx_compose is a simple syntax extension which rewrites code containing
function compositions into composition-free code, effectively inlining the
composition operators. The following two operators are supported

let (%) g f x = g (f x)
let (%>) f g x = g (f x)

Corresponding definitions are not provided, so partial applications of (%)
and (%>) will be undefined unless you provide the definitions.

The following rewrites are done:

A composition occurring to the left of an application is reduced by
applying each term of the composition from right to left to the
argument, ignoring associative variations.

A composition which is not the left side of an application is first
turned into one by η-expansion, then the above rule applies.

Any partially applied composition operators are passed though unchanged.